Know Your Environment. Protect Your Health.

Fluoride

Monona Waterworks

Fluoride occurs naturally in surface and groundwater and is also added to drinking water by many water systems to prevent cavities and support oral health in people.

In 2015, the Department of Health and Human Services updated its recommendation of an optimal level of 0.7 parts per million, or ppm, added to drinking water based on the health benefits of tooth decay prevention. Studies have shown that fluoride added to community water systems at this level reduces dental cavities, especially in children.

And studies have conclusively shown that fluoride in toothpaste and mouthwash can also provide these benefits. Read More.

Health Concerns

Although the HHS-recommended level of 0.7 ppm can help promote oral health in children and adults, this level is likely too high for bottle-fed babies. EWG recommends that caregivers mix baby formula with fluoride-free water.

And fluoride in water at higher levels can be detrimental for everyone, especially children.

Long-term ingestion of higher levels of fluoride in water increases dental fluorosis, which includes mottling, pitting and weakening of the teeth in children.

A 2024 authoritative assessment by the National Toxicology Program found that higher levels of fluoride exposure, such as drinking water containing more than 1.5 ppm of fluoride, are associated with lower IQ in children. The conclusion was based on studies in human populations outside of the U.S.

Affecting systems with naturally occurring fluoride, EPA’s maximum legal limit is set at 4 parts per million (ppm) to prevent skeletal fluorosis, a condition where bones become brittle and more susceptible to fracture. But these effects may occur at lower levels of exposure, raising concerns that the current limit may not adequately protect public health.

 

147

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.677 ppm24240.570 ppm - 0.830 ppm
20190.679 ppm24240.510 ppm - 0.830 ppm
20200.657 ppm22220.530 ppm - 0.870 ppm
20210.569 ppm26260.410 ppm - 0.731 ppm
20220.632 ppm24240.490 ppm - 0.840 ppm
20230.545 ppm27270.0851 ppm - 0.810 ppm

ppm = parts per million

State, National, and Health Guidelines for Drinking Water

EPA Maximum Contaminant
Level (MCL): 4 ppm

ppm = parts per million

All test results

Date Lab ID Result
2018-01-303646670010.656 ppm
2018-01-303646670010.670 ppm
2018-02-133666670010.640 ppm
2018-02-133666670010.674 ppm
2018-03-053691810010.696 ppm
2018-03-053691810010.830 ppm
2018-04-023737350010.674 ppm
2018-04-023737350010.690 ppm
2018-05-073799700010.703 ppm
2018-05-073799700010.710 ppm
2018-06-203899650010.659 ppm
2018-06-203899650010.690 ppm
2018-07-193956800010.650 ppm
2018-07-193956800010.730 ppm
2018-08-033984800010.675 ppm
2018-08-033984800010.740 ppm
2018-09-194090150010.570 ppm
2018-09-194090150010.633 ppm
2018-10-244162450010.600 ppm
2018-10-244162450010.675 ppm
2018-11-064181080010.653 ppm
2018-11-064181080010.710 ppm
2018-12-054226950010.592 ppm
2018-12-054226950010.720 ppm
2019-01-154278430010.618 ppm
2019-01-154278430010.730 ppm
2019-02-204323400010.699 ppm
2019-02-204323400010.830 ppm
2019-03-074342460010.741 ppm
2019-03-074342460010.760 ppm
2019-04-034385480010.676 ppm
2019-04-034385480010.720 ppm
2019-05-084447920010.660 ppm
2019-05-084447920010.790 ppm
2019-06-054499930010.694 ppm
2019-06-054499930010.770 ppm
2019-07-084556300010.599 ppm
2019-07-084556300010.610 ppm
2019-08-284664370010.619 ppm
2019-08-284664370010.660 ppm
2019-09-054678580010.663 ppm
2019-09-054678580010.770 ppm
2019-10-164766270010.510 ppm
2019-10-164766270010.627 ppm
2019-11-074803110010.613 ppm
2019-11-074803110010.740 ppm
2019-12-044843160010.570 ppm
2019-12-044843160010.622 ppm
2020-01-094886370010.710 ppm
2020-01-094886370010.870 ppm
2020-04-135004010010.662 ppm
2020-04-135004010010.760 ppm
2020-05-055031470010.636 ppm
2020-05-055031470010.760 ppm
2020-06-085082320010.530 ppm
2020-06-085082320010.579 ppm
2020-07-065127680010.612 ppm
2020-07-065127680010.650 ppm
2020-08-055183290010.636 ppm
2020-08-055183290010.850 ppm
2020-09-025231210010.610 ppm
2020-09-025231210010.626 ppm
2020-09-165257730010.600 ppm
2020-09-165257730010.645 ppm
2020-10-155314010010.560 ppm
2020-10-155314010010.650 ppm
2020-11-025338560010.636 ppm
2020-11-025338560010.670 ppm
2020-12-015378600010.570 ppm
2020-12-015378600010.635 ppm
2021-01-055421280010.645 ppm
2021-01-055421280010.690 ppm
2021-03-015491040010.462 ppm
2021-03-015491040010.680 ppm
2021-03-015491040010.462 ppm
2021-03-015491040010.680 ppm
2021-04-055541820010.481 ppm
2021-04-055541820010.720 ppm
2021-04-235579760010.484 ppm
2021-04-235579760010.530 ppm
2021-05-035592070010.551 ppm
2021-05-035592070010.590 ppm
2021-06-035648750010.580 ppm
2021-06-035648750010.731 ppm
2021-07-125714450010.460 ppm
2021-07-125714450010.500 ppm
2021-08-025754480010.420 ppm
2021-08-025754480010.429 ppm
2021-09-075817140010.625 ppm
2021-09-075817140010.660 ppm
2021-10-015871530010.631 ppm
2021-10-015871530010.640 ppm
2021-11-025925580010.410 ppm
2021-11-025925580010.569 ppm
2021-12-025967010010.541 ppm
2021-12-025967010010.610 ppm
2022-01-036002680010.568 ppm
2022-01-036002680010.660 ppm
2022-02-046045280010.600 ppm
2022-02-046045280010.602 ppm
2022-03-046080620010.623 ppm
2022-03-046080620010.720 ppm
2022-04-016117330010.626 ppm
2022-04-016117330010.690 ppm
2022-05-036169100010.670 ppm
2022-05-036169100010.673 ppm
2022-06-016224510010.679 ppm
2022-06-016224510010.840 ppm
2022-07-056282730010.490 ppm
2022-07-056282730010.622 ppm
2022-08-086354370010.578 ppm
2022-08-086354370010.630 ppm
2022-09-016401720010.657 ppm
2022-09-016401720010.740 ppm
2022-10-036459840010.567 ppm
2022-10-036459840010.620 ppm
2022-11-046517180010.572 ppm
2022-11-046517180010.600 ppm
2022-12-056554150010.540 ppm
2022-12-056554150010.596 ppm
2023-01-056595230010.525 ppm
2023-01-056595230010.560 ppm
2023-02-016627120010.551 ppm
2023-02-016627120010.650 ppm
2023-03-026664760010.488 ppm
2023-03-026664760010.600 ppm
2023-03-176688800010.0851 ppm
2023-03-176688790010.108 ppm
2023-03-176689440010.112 ppm
2023-04-056716400010.486 ppm
2023-04-056716400010.600 ppm
2023-05-086770000010.600 ppm
2023-05-086770000010.810 ppm
2023-06-056817140010.546 ppm
2023-06-056817140010.700 ppm
2023-07-056867060010.610 ppm
2023-07-056867060010.670 ppm
2023-08-016921250010.525 ppm
2023-08-016921250010.700 ppm
2023-09-066986310010.650 ppm
2023-09-066986310010.670 ppm
2023-10-027035900010.641 ppm
2023-10-027035900010.730 ppm
2023-11-077094800010.530 ppm
2023-11-077094800010.547 ppm
2023-12-047128360010.480 ppm
2023-12-047128360010.548 ppm